Generation of 4′-Carbon Radicals via 1,5-Hydrogen Atom Transfer for the Synthesis of Bridged Nucleosides

Ito, Yuta; Mizuno, Koichi; Sumise, Sanae; Kimura, Airi; Noguchi, Nozomi; Fuchi, Yasufumi; Hari, Yoshiyuki

doi:10.1021/acs.orglett.2c03285

“…A different synthetic approach, that is related to the generation of imidate radicals using blue LED to form 2'-O,4'-Cand 3'-O,4'-C-bridged nucleosides, was reported in 2022. [86] Nphenoxybenzimidates substituted nucleosides that contain an allylic 198 or propargylic 202 moiety were used as substrates. In the presence of fac-Ir(ppy) 3 199 as the photocatalyst and under blue LED, N-radicals XXVII were produced and simultaneously via 1,5-HAT the corresponding 4'-carbon radicals XXVIII were obtained to undergo an intramolecular cyclization and provide the desired products 200 (Scheme 52).…”

Section: Metal Complexes Of Imidatesmentioning

confidence: 99%

“…A different synthetic approach, that is related to the generation of imidate radicals using blue LED to form 2’‐ O ,4’‐ C ‐ and 3’‐ O ,4’‐ C ‐bridged nucleosides, was reported in 2022 [86] . N ‐phenoxybenzimidates substituted nucleosides that contain an allylic 198 or propargylic 202 moiety were used as substrates.…”

Section: Diverse Applications Of Imidatesmentioning

confidence: 99%

Synthetic Routes to Imidates and Their Applications in Organic Transformation: Recent Progress

Chaidali,

Lykakis

2023

Eur J Org Chem

3

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Recent synthetic approaches and diverse applications of imidates are presented in this review. These motifs are successfully used as intermediates in organic transformations, such as the synthesis of N‐heterocycles, natural products and metal complexes with a potential catalytic effect. Consequently, many attempts have been made for the development of efficient and facile synthetic methods of imidates in the past few years, as a continuum of previous paths. A wide range of organic compounds can be used as starting materials for these syntheses, including nitriles, isocyanides, amides etc. which through simple and flexible processes are converted to the desired imidates. Herein, an exploration of the recent synthetic routes of imidates and their diverse applications in organic transformations has been categorized and summarized.

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PolyBorylated Alkenes as Energy‐Transfer Reactive Groups: Access to Multi‐Borylated Cyclobutanes Combined with Hydrogen Atom Transfer Event

Hanania,

Eghbarieh,

Masarwa

2024

Angewandte Chemie

0

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While polyborylated alkenes are being recognized for their elevated status as highly valuable reagents in modern organic synthesis, allowing efficient access to a diverse array of transformations, including the formation of C–C and C–heteroatom bonds, their potential as energy‐transfer reactive groups has remained unexplored. Yet, this potential holds the key to generating elusive polyborylated biradical species, which can be captured by olefins, thereby leading to the construction of new highly‐borylated scaffolds. Herein, we report a designed energy‐transfer strategy for photosensitized [2+2]‐cycloadditions of poly‐borylated alkenes with various olefins enabling the regioselective synthesis of diverse poly‐borylated cyclobutane motifs, including the 1,1‐di‐, 1,1,2‐tri‐, and 1,1,2,2‐tetra‐borylated cyclobutanes. In fact, these compounds belong to a family that presently lacks efficient synthetic pathways. Interestingly, when α‐methylstyrene was used, the reaction involves an interesting 1,5‐hydrogen atom transfer. Mechanistic deuterium‐labeling studies have provided insight into the outcome of 1,5‐hydrogen atom transfer process. In addition, the polyborylated cyclobutanes are then demonstrated to be useful in selective oxidation processes resulting in the formation of cyclobutanones and γ‐lactones.

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PolyBorylated Alkenes as Energy‐Transfer Reactive Groups: Access to Multi‐Borylated Cyclobutanes Combined with Hydrogen Atom Transfer Event

Hanania,

Eghbarieh,

Masarwa

2024

Angew Chem Int Ed

5

0

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While polyborylated alkenes are being recognized for their elevated status as highly valuable reagents in modern organic synthesis, allowing efficient access to a diverse array of transformations, including the formation of C–C and C–heteroatom bonds, their potential as energy‐transfer reactive groups has remained unexplored. Yet, this potential holds the key to generating elusive polyborylated biradical species, which can be captured by olefins, thereby leading to the construction of new highly‐borylated scaffolds. Herein, we report a designed energy‐transfer strategy for photosensitized [2+2]‐cycloadditions of poly‐borylated alkenes with various olefins enabling the regioselective synthesis of diverse poly‐borylated cyclobutane motifs, including the 1,1‐di‐, 1,1,2‐tri‐, and 1,1,2,2‐tetra‐borylated cyclobutanes. In fact, these compounds belong to a family that presently lacks efficient synthetic pathways. Interestingly, when α‐methylstyrene was used, the reaction involves an interesting 1,5‐hydrogen atom transfer. Mechanistic deuterium‐labeling studies have provided insight into the outcome of 1,5‐hydrogen atom transfer process. In addition, the polyborylated cyclobutanes are then demonstrated to be useful in selective oxidation processes resulting in the formation of cyclobutanones and γ‐lactones.

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Generation of 4′-Carbon Radicals via 1,5-Hydrogen Atom Transfer for the Synthesis of Bridged Nucleosides

Cited by 4 publications

References 36 publications

Synthetic Routes to Imidates and Their Applications in Organic Transformation: Recent Progress

Synthetic Routes to Imidates and Their Applications in Organic Transformation: Recent Progress

PolyBorylated Alkenes as Energy‐Transfer Reactive Groups: Access to Multi‐Borylated Cyclobutanes Combined with Hydrogen Atom Transfer Event

PolyBorylated Alkenes as Energy‐Transfer Reactive Groups: Access to Multi‐Borylated Cyclobutanes Combined with Hydrogen Atom Transfer Event

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